Can the school give out this info?

If a parent is a drug addict and lost custody (no visitation or anything) because of neglect and drugs and not taking her child to school, can a child's old school legally tell the parent who lost custody, where the child's new school is, if the parent with custody is keeping the child away from that parent until they get better?

**EDIT**

The old school knows, the old school told her where he goes to school now. and I guess the old school told the new school that she was told and the new school contacted us and told us that she knows. And said she had a "right" to know. But in this situation, I feel like she doesn't have a right to find out from anyone else but the parent with custody.